A disc drive includes a plurality of stacked discs which are rotationally supported relative to a disc spindle and an actuator assembly movably supporting a plurality of head gimbal assemblies for reading and writing data to the discs. The actuator assembly includes an actuator drive typically a voice coil motor for actuating the head gimbal assemblies relative to selected data tracks of the discs.
The voice coil motor includes a magnet assembly defining a permanent magnetic field and a energizable coil coupled to an actuator block supporting the head gimbal assemblies. A voltage is supplied to the coil to selectively operate and move the actuator block to align the head gimbal assemblies relative to predetermined data tracks of the discs.
A typical magnet assembly includes upper and lower pole plates or backirons which are supported relative to the disc drive assembly in a spaced relation and include a magnet coupled thereto to define a flux gap therebetween. An energized coil moves in the flux gap between the upper and lower pole plates.
For proper operation of the voice coil motor, the magnets must be accurately aligned and assembled to upper and lower pole plates; and upper and lower pole plates should be accurately aligned and connected for accurate head placement relative to selected data tracks. The magnet components should be assembled to limit the release of magnetic debris which may contaminate the disc drive and interfere with read/write operations of the disc drive.
The present invention addresses these and other problems, and offers advantages over the prior art.